Screws with heads requiring special tools for turning the screw are well known and have been used in the past to prevent tampering or unauthorized removal by persons lacking the special tool, which will be referred to hereafter as the key. In other words, unauthorized removal of the screw is thwarted because the screw cannot be turned with tools other than the special key.
In outdoor environments, especially areas accessible to the general public, unauthorized persons may be tempted to remove ordinary type screw fasteners and thereby enter enclosures secured by these fasteners, which can lead to damage of the fasteners, or theft, damage or other loss of equipment or other valuables within the enclosures. One important use of such screw type fasteners is to lock telephone equipment within a protective enclosure. The protective enclosure may be an above-ground shed or cabinet having a screw-secured door, or may be an underground chamber having a screw secured cover, such as a manhole cover. Although the prior art discloses many fasteners of the screw type, that are said to be tamper-resistant, these fasteners and the special tools for operating them are difficult and expensive to manufacture.